I really like the UCO Stormproof matches, and I have quite a few of them. FWIW the matches I just got are older ones but still sealed in celophane; they're the old Diamond ones. I opened a box to try them and they do indeed reliably strike on kydex, and they worked on a DMT diamond sharpening stone I had laying around.

Obviously they're a curio. Once I use them them up there won't be any more, and certainly the limited remaining stock will get scarcer and poorer as they 'age'. Just wanted a few high quality SA for my kits.
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“I'd rather have questions that cannot be answered than answers that can't be questioned.” —Richard Feynman